Physical fitness as a mediator between objectively measured physical activity and clustered metabolic syndrome in children and adolescents: The UP&DOWN study

Comparison of Metabolic Risk Factors Based on the Type of Physical Activity in Korean Adolescents: Results from a Nationwide Population-Based Survey

BACKGROUND

Physical activity (PA) is associated with a favorable metabolic risk profile in adults. However, its role in adolescents remains unclear. In this study, using data (2019-2021) from the 8th Korea National Health and Nutrition Examination Survey, we investigated the optimal exercise type for preventing metabolic complications in adolescents.

METHODS

A total of 1,222 eligible adolescent participants (12-18-year-old) were divided into four groups as follows: aerobic exercise (AE), resistance exercise (RE), combined aerobic and resistance exercise (CE), and no exercise (NE). Daily PA was assessed using the international PA questionnaire. Blood samples were collected to measure lipid, glucose, and insulin levels. Additionally, the homeostasis model assessment for insulin resistance (HOMA-IR) and triglyceride-glucose (TyG) indices were measured. Multivariate regression analysis was used to compare the metabolic risk factors across the PA groups before and after propensity score matching (PSM) adjustment for confounding variables.

RESULTS

The CE group exhibited improved fasting glucose levels, lower TyG index, reduced white blood cell count, and higher high-density lipoprotein (HDL) cholesterol levels than the NE group. The RE group exhibited lower mean blood pressure, triglyceride, fasting insulin, HOMA-IR, TyG index and a reduced risk of metabolic syndrome than the NE group. The AE group had higher total and HDL cholesterol levels. In detailed comparison of the AE and RE groups, the RE group consistently exhibited favorable metabolic parameters, including lower blood pressure and total and low-density cholesterol levels, which persisted after PSM.

CONCLUSION

These findings highlight the positive effects of PA on cardiovascular risk factors in adolescents. Thus, RE may have a more favorable metabolic effect than AE. Further studies are needed to validate the benefits of exercise according to the exercise type.

Imbalanced dietary patterns, anthropometric, and body composition profiles amongst adults with Down syndrome

Introduction: We aimed to analyze the anthropometric and body composition profiles of Down syndrome (DS) adults; to describe their dietary habits, nutrient intake, and physical activity patterns; and to identify the related risk factors which may influence their health status and quality of life.Methods: A cross-sectional study was conducted on a cohort of 23 DS adults (45% women) aged 21-44 years. Anthropometry and body composition were assessed by bioelectrical impedance. Dietary nutrient intake was assessed quantitatively using a 72-h recall. A food frequency questionnaire and the prevention with Mediterranean diet-PREDIMED questionnaire were used for qualitative rating.Results: Higher fat mass (FM) and lower lean mass (LM), bone mass (BM), and waist to hip ratio (WHR) were observed in women compared to men. LM and BM decreased, and body mass index (BMI), FM, and WHR increased with aging (all P < 0.05). Vitamin D and iodine intakes were not met by 70% and 60% of the studied participants, respectively. A total of 82% of the participants consumed less than 5 portions of fruits and vegetables per day and overconsumed food groups such as sweets and snacks and red meat (> 2 times per week). Protein intake showed a significant positive correlation with height (r = 0.489, P < 0.05), whereas fat intake was positively correlated with sweets and snacks (r = 0.521, P < 0.05).Conclusion: The present findings support the existence of poor anthropometric and body composition profiles, and diet quality, underscoring the need for an interdisciplinary team assessment to enhance health and quality of life in DS adults.

Influence of Volume and Bouts of Sedentary Time and Physical Activity on School-Aged Youth's Physical Fitness: The UP & DOWN Longitudinal Study

BACKGROUND

The aim of this study was to examine associations of total volume and bouts of sedentary time (ST) and moderate to vigorous physical activity (MVPA) with physical fitness (PF) in youth.

METHODS

This was a 2-year follow-up study with 1418 children and adolescents (51.7% boys). Accelerometers were used to assess ST and MVPA. Cardiorespiratory and muscular fitness values were objectively measured and combined in a global PF variable. Weight status was objectively obtained. Linear regression analyses were used to examine the cross-sectional (using scores at baseline) and longitudinal associations (using the change in the variables) of total volume and bouts of ST and MVPA with PF.

RESULTS

Total ST was negatively associated with global PF (β = -0.488, P < .001 in cross-sectional analysis; β = -0.234, P = .003 in longitudinal analysis). However, this association was not independent of MVPA. Total volume of MVPA showed a positive association with global PF independently of ST and weight status (β = 0.285, P < .001 in cross-sectional analysis; β = 0.119, P = .001 in longitudinal analysis). Longitudinal associations found between ST and MVPA accumulated in bouts of various lengths and global PF became nonsignificant when their respective total volumes are included in the model.

CONCLUSIONS

These results underline the need to accumulate minutes of MVPA, regardless of the bout duration, to increase PF levels in youth.

Cardiorespiratory Fitness, Obesity and Physical Activity in Schoolchildren: The Effect of Mediation

There are only a few studies that have examined the interaction between physical activity (PA), cardiorespiratory fitness (CRF), and overweightness/obesity in adolescents, and these studies have shown some limitations. The objective of this study was to examine whether the association between PA (moderate-vigorous PA [MVPA], moderate PA [MPA], and vigorous PA [VPA]) and obesity is mediated by CRF. This cross-sectional study was conducted in six middle and high-schools in the Porto district (Portugal), comprising 632 children and adolescents. Fat mass (FM), CRF, MVPA, MPA, and VPA were assessed. The Process macro for SPSS was used. CRF was significantly associated with PA for both children and adolescents. Likewise, FM was negatively and significantly associated with CRF for both children (β = -0.337) and adolescents (β = -0.255). FM was associated with PA in children (MVPA: β = -0.102; MPA: β = -0.118; VPA: β = -0.305) and adolescents (MVPA: β: -0.103; MPA: β = -0.082; VPA: β = -0.204). The mediation analysis showed that the association between PA (MVPA//MPA/VPA) and obesity was mediated by CRF, in both children and adolescents, with a significant value in the Sobel test. Obesity is associated with CRF and MVPA, MPA, and VPA. However, CRF acted as a complete mediator between the association of obesity and PA.

Metabolic syndrome: Operational definitions and aerobic and resistance training benefits on physical and metabolic health in children and adolescents

BACKGROUND

The variation in parameters for childhood metabolic syndrome (MetS) has hindered the development of a consensus for the diagnostic criteria in this group. Despite these inconsistencies, it is accepted that exercise can ameliorate the deleterious effects of MetS. However, direct comparison between aerobic versus resistance exercise on MetS symptomology in adolescents is lacking.

AIM

Aim of this review was to discuss controversies associated with current MetS operation definitions in adolescents and present a review summarizing longitudinal studies relevant to the influence of aerobic and resistance training on children with MetS.

METHODS

Reviews of PubMed and Web of Science were conducted to identify literature focusing on the influence of aerobic and resistance training on children with MetS. Selected manuscripts featured longitudinal research only.

RESULTS

A universally accepted definition of MetS for the pediatric population has yet to be established. As such, consensus regarding diagnostic criteria for MetS among children is lacking despite the presence of various descriptions in the literature. Though studies support the importance of aerobic and resistance exercise to combat comorbidities associated with MetS, longitudinal studies investigating the benefits of each exercise type among adolescents are limited and inconsistent.

CONCLUSION

An improved understanding of the impact of aerobic and resistance training on children with MetS is clinically relevant because it may facilitate more appropriate exercise recommendations for children with MetS. Additional large cohort studies are warranted to determine optimal exercise type.

The Effect of Physical Exercise on Fundamental Movement Skills and Physical Fitness among Preschool Children: Study Protocol for a Cluster-Randomized Controlled Trial

Background: Evidence shows that physical exercise promotes preschoolers’ fundamental movement skills (FMSs) and physical fitness (PF). However, studies that assess the effectiveness of different types of physical exercise interventions to improve FMSs and PF in preschool children remain scarce. To explore and compare the effectiveness of different physical exercise on FMSs and PF, interventions comprising ball games (BGs), rhythm activities (RAs), basic movements (BMs), and a combination of all related activities (multiple activities, MAs) will be conducted among preschoolers. Methods: A single-blind, five-arm, cluster-randomized trial will be conducted in kindergarten in Shanghai, China. In total, 300 healthy preschoolers, aged 4 to 5 years, will be randomized to four intervention groups (BG, RA, BM, or MA) and one control group (unorganized physical activities). Four intervention groups will receive three 30-min lessons weekly for 16 weeks. At the baseline, the end of the 16-week intervention, and the 6-month follow-up after the end of the intervention, the primary outcomes (FMSs and PF) and physical activity (PA), and sociodemographic and anthropometric data will be assessed. Discussion: This study will provide vital information regarding the effect of different physical exercise interventions on preschool children’s FMSs and PF, PA, and the potential interactions between these domains. The most effective intervention strategy can be generalized to kindergarten and other preschool educational institutions in practice to promote preschoolers’ development of FMSs and PF. Conclusions: This study protocol aims to provide a method to solve the problem of “how to arrange physical exercise and which kind of physical exercise program can promote FMS and PF better in preschool children”.

Is Motivation Associated with Mental Fatigue during Padel Trainings? A Pilot Study

Motivation seems to enhance athletes’ mental efforts, but this has not been tested yet in padel. The objective was to test the effects of motivation on mental fatigue during padel trainings. Thirty-six elite youth players participated (twenty-two males, Mage = 17.40, SDage = 2.16, and fourteen females, Mage = 17.90, SDage = 3.21). We designed four padel training matches, introducing a constraint in two of them in a counterbalanced order. The constraint was: Couples that win more sets in these two matches obtain a free lesson with a professional padel player. Motivation was quantified by a questionnaire before the matches. Moreover, subjective feelings of mental load and fatigue were measured with questionnaires, and objective measures of fatigue were quantified through heart-rate variability and reaction time. Results suggest that the constraint significantly increases motivation (p < 0.001). Furthermore, in these matches, players reported significantly higher feelings and objective measures of fatigue (p < 0.001 for HRV and VAS; p = 0.04 for reaction time). An increase in the resources used by the neural facilitation system, mediated by higher values of motivation, seems a relevant candidate to explain this phenomenon.

Mediation role of cardiorespiratory fitness on the association between fatness and cardiometabolic risk in European adolescents: The HELENA study

PURPOSE

This study was aimed to analyze the mediation role of cardiorespiratory fitness (CRF) on the association between fatness and cardiometabolic risk scores (CMRs) in European adolescents.

METHODS

A cross-sectional study was conducted in adolescents (n = 525; 46% boys; 14.1 ± 1.1 years old, mean ± SD) from 10 European cities involved in the Healthy Lifestyle in Europe by Nutrition in Adolescence study. CRF was measured by means of the shuttle run test, while fatness measures included body mass index (BMI), waist to height ratio, and fat mass index estimated from skinfold thicknesses. A clustered CMRs was computed by summing the standardized values of homeostasis model assessment, systolic blood pressure, triglycerides, total cholesterol/high-density lipoprotein cholesterol ratio, and leptin.

RESULTS

Linear regression models indicated that CRF acted as an important and partial mediator in the association between fatness and CMRs in 12-17-year-old adolescents (for BMI: coefficients of the indirect role β = 0.058 (95% confidence interval (95%CI): 0.023-0.101), Sobel test z = 3.11 (10.0% mediation); for waist to height ratio: β = 4.279 (95%CI: 2.242-7.059), z =3.86 (11.5% mediation); and for fat mass index: β = 0.060 (95%CI: 0.020-0.106), z = 2.85 (9.4% mediation); all p < 0.01).

CONCLUSION

In adolescents, the association between fatness and CMRs could be partially decreased with improvements to fitness levels; therefore, CRF contribution both in the clinical field and public health could be important to consider and promote in adolescents independently of their fatness levels.

Effects of physical fitness training on metabolic syndrome among military personnel in Taiwan

INTRODUCTION

Metabolic syndrome (MS) is strongly associated with cardiovascular diseases and diabetes but can be prevented with regular physical activity. This study aimed to assess the impact of a physical fitness training programme on MS among military personnel.

METHODS

This retrospective observational study included volunteer army soldiers who underwent annual health examinations between 2011 and 2014. In 2011, the reformed physical fitness training programme and physical fitness test were introduced to the participants. MS evaluation and physical fitness performances were evaluated before and after implementing the training programme using a mixed-effects model and generalised estimating equation, adjusted for sex, age and smoking.

RESULTS

From 2011 to 2014, 1720 soldiers underwent the annual health examination. In 2011, before the fitness programme, 246 soldiers (14.3%) had MS. After implementation, decreases in blood pressure and fasting glucose levels were observed and maintained for 3 years. Running performance was negatively correlated to triglycerides (ß=-11.37; p<0.001) and waist circumference (ß=-0.42; p<0.001) and positively correlated to high-density lipoprotein cholesterol levels (ß=2.14; p<0.001). The severity of MS was reduced following introduction of the physical fitness programme.

CONCLUSIONS

MS and its components improved after introducing the reformed fitness programme, with running performance proving to be most relevant to MS. Clinicians should encourage increased physical activity to prevent MS among military personnel.

Effect modification by cardiorespiratory fitness on the association between physical activity and cardiometabolic health in youth: A systematic review

Physical activity and cardiorespiratory fitness are inversely associated with markers of cardiometabolic risk in children and adolescents, but the interplay between these variables in relation to the cardiometabolic risk profile is unclear. We systematically reviewed the literature to examine whether the association between physical activity and cardiometabolic health differs by levels of cardiorespiratory fitness in youth. A literature search was conducted in PubMed and EMBASE, filtered from 2001 up until July 2019. We obtained 8980 citations, with 6915 remaining after removal of duplicates. Estimates were retrieved from 18 studies. All included articles went through a risk of bias assessment. We found that 14 out of 20 (70%) effect-estimates supported stronger associations between physical activity and cardiometabolic health markers among low-fit youth as compared to their high-fit peers. The most consistent findings were observed with biochemical markers and blood pressure as outcomes. However, substantial uncertainty is associated with these findings as most of the included studies (~72%) had a high risk of bias. More than two-thirds of the findings supported greatest benefits of physical activity on cardiometabolic risk markers in youth with low cardiorespiratory fitness, although the clinical importance of this difference is unclear.

Relationship Between the Practice of Physical Activity and Physical Fitness in Physical Education Students: The Integrated Regulation As a Mediating Variable

The practice of physical activity (PA) contributes to the prevention of chronic diseases such as obesity, metabolic syndrome or cardiovascular diseases, being also directly related to the individual’s physical fitness. Therefore, it is necessary to measure and monitoring the levels of PA in childhood and adolescence, since it may be useful to describe their current health status and the association with physical fitness, as well as to reveal putative consequences in the future. Within the educational field, it has been shown that physical education (PE) classes are a favorable context for the creation of healthy physical-sports habits and self-determined motivation could be a key for explaining the level of PA practice. For this reason, the purpose of this research was to study the mediating role of integrated regulation (IR) on the relationship between PA and physical fitness in children and adolescents. A total of 325 students between 11 and 14 years old participated in the study. The level of PA was estimated through the specific Physical Activity Questionnaire for Children (PAQ-C), while motivation and IR were measured by using the Perceived Locus of Causality scale (PLOC-2). In addition, physical fitness was measured through the Eurofit fitness battery of tests, composed of three body composition measures and seven tests of different physical capacities. The physical fitness score showed no differences when genders were compared. After regression analysis, the resulting models revealed a good adjustment and correlation between PA practice and physical fitness (β = 0.173; p < 0.001), being established through the macro Process that this relationship is partially conditioned by the IR (β = 0.122; p = 0.03). ROC curve analysis estimated the score of 5.88 as a cut-off point to discriminate between levels of IR for students, classified as physically active or not (AUC = 0.67; p < 0.001). The conclusions from these main and other complementary analyses reporting complete mediations, suggest that the IR could be decisive in predicting and explaining the relationship between the practice of PA and physical fitness at these ages, highlighting its importance for a greater adherence to the practice.

Associations between Weight Status and Situational Motivation toward Fitness Testing in Physical Education: The Mediator Role of Physical Fitness

Background: This article examines the differences in situational motivation toward fitness testing in physical education classes between non-overweight and overweight students, as well as the mediator effect of objective and perceived physical fitness on the relationship between weight status and motivation toward fitness testing. Methods: A total of 534 adolescents (298 boys, 55.80%) participated in the study. Perceived physical fitness and situational motivation toward fitness testing were measured through questionnaires, whereas weight status and physical fitness were objectively measured. Results: Overweight students had lower intrinsic motivation (p < 0.001), and higher external regulation (p < 0.01) and amotivation (p < 0.05) during fitness testing in a physical education class than their non-overweight peers. The influence of being overweight on motivation regulations toward fitness testing was mediated by objective physical fitness level for intrinsic motivation (B = −0.140), external regulation (B = 0.104) and amotivation (B = 0.146). Perceived physical fitness was also used as a second mediator between weight status and intrinsic motivation (B = −0.117). Conclusions: Strategies to improve objective and perceived physical fitness in overweight students are necessary to increase self-determined motivation during fitness testing in physical education lesson.

Fitness as a Mediator of the Enhancement of Quality of Life after a 6-Months Exercise Program

Purpose: The study aimed to test whether improvement in fitness components, mediates the changes in Health-related Quality of Life (HRQoL) after exercise intervention in overweight and obese children. Methods and design: 170 obese and overweight children (121 exercise group and 49 control group) participated in a public exercise program based on sports practice for 6 months, 2 h per week. Anthropometry, physical fitness, and HRQoL were measured. Magnitude-based inferences and Cohen's effect size were performed to analyze the program effect. To know which physical fitness components mediated the improvement on children's HRQoL, multiple mediation analyses were performed. Results: the analysis showed a moderate effect on some fitness components and a moderate and small effect on HRQoL. The improvement of agility or cardiorespiratory fitness showed a significant indirect effect on the enhancements in some HRQoL dimensions. Conclusion: after a 6-months exercise program in overweight and obese children, all physical fitness components improved, being responsible for the improvement of the HRQoL, agility and cardiorespiratory fitness.

Physical fitness and nutritional status in female adolescents with anorexia nervosa

ABSTRACT Objective This study aimed to determine whether physical fitness is related to nutritional status in a sample of female adolescents with anorexia nervosa, to contrast the nourished and undernourished patients, and to compare the physical fitness in these patients with normative data of healthy subjects stratified by age and gender. Methods Nutritional status was determined using the body mass index Z-score, fat mass, fat-free mass (bioelectrical impedance analysis), and the Controlling Nutritional Status score in 15 anorexic adolescents with 14.3±1.6 years. Physical fitness was assessed using the ALPHA-Fitness Battery (handgrip strength, standing broad jump, 4x10m shuttle run, and 20m shuttle run tests). Results Handgrip strength was significantly associated with all variables of nutritional status, except with the three blood components of the Controlling Nutritional Status score. The undernourished anorexic patients showed significantly worse physical fitness than the nourished anorexic patients in all tests, except in the standing broad jump and the 4x10m shuttle run tests. The physical fitness tests of the female anorexic adolescents showed scores significantly worse than those of the normative European female adolescent population. Conclusion The observation of female adolescents with anorexia nervosa showed associations between higher physical fitness levels and better nutritional statuses. Handgrip strength and 20m shuttle run tests may be options of additional indicators of undernutrition in anorexic female adolescents. The undernourished anorexic patients showed worse physical fitness than the nourished ones. According to normative data for healthy sex- and agematched adolescents, physical fitness is severely impaired in anorexic female adolescents.

Physical Activity Practice and Healthy Lifestyles Related to Resting Heart Rate in Health Sciences First-Year Students

The expression lifestyle describes a frame of expressed behaviors, usually in the form of patterns of consumption, that defines how an individual or social group fits into society. It presents as a focus of interest by researchers in this field, who classically favor the study of alcohol consumption, tobacco, eating habits, and physical activity. The aim of this study was to identify the relationship between physical activity and healthy lifestyles, especially in terms of eating habits, tobacco, alcohol consumption, resting habits, and resting heart rate (RHR) in Health Sciences first-year students. A total of 177 students of both genders participated, of whom 31 (17.5%) were male and 146 (82.5%) were female, with a mean age of 20.20 years, from 18 to 30 years. The data collection instrument used was the Healthy Lifestyle Questionnaire (EVS), using SPSS 21.0 for descriptive statistics and the Cronbach α to evaluate the internal consistency of the questionnaires. A level of significance was adopted with a margin of error of 5% for a probability of at least 95% using the Kolmogorov-Smirnov technique and Mann-Whitney test for comparisons between practitioners’ students and genders. The results obtained demonstrate more favorable results in all variables in students practicing physical activity with significant differences in eating habits and RHR. In terms of gender, there were significant differences in all variables except for eating habits. We conclude that students practicing physical activity present more favorable results in terms of lifestyles combined with lower RHR values, considered as positive factors in terms of quality of life.

Cardiorespiratory Fitness as a Mediator of the Association between Physical Activity and Overweight and Obesity in Adolescent Girls

Background: Overweight and obesity (OW/OB) continue to be prominent health issues among adolescent girls. However, little is known about the interrelationships between physical activity (PA), cardiorespiratory fitness (CRF), and OW/OB in this population. The objective of this study was to examine whether CRF mediates the relationship between PA and OW/OB in adolescent girls. Methods: Moderate-to-vigorous PA (MVPA), CRF, BMI, and percentage body fat (% BF) were measured in adolescent girls (N = 1519), aged 10-14 years, from 24 urban middle schools located in the Midwestern United States. Structural equation modeling was used to determine whether CRF is a mediator of the association between MVPA and OW/OB (measured as both BMI and % BF). Multigroup analyses were used to determine whether race, puberty, or socioeconomic status moderate the mediation models. Results: The indirect effect of MVPA through CRF on OW/OB was significant for both BMI (p < 0.01) and % BF (p < 0.01), indicating that CRF is a complete mediator between MVPA and OW/OB. Both race and puberty significantly (p < 0.05) moderated the mediation between MVPA and OW/OB. Conclusions: This study demonstrates that CRF is improved by increasing MVPA, and the improvement in CRF results in lower BMI and % BF among adolescent girls.

Active streets for children: The case of the Bogotá Ciclovía

Introduction

The Ciclovía is a worldwide program in which streets are temporarily closed to motorized transport to create a space for recreation and outdoor play among children and adults. The aim of this study was to assess the associations between physical activity (PA), sedentary time (SED), body mass index and Ciclovía participation among children aged 9 to 13 years.

Methods

All students in the 4^th and 5^th grades from the selected schools were invited to participate in the study. The study included 923 children. PA and SED were measured using waist-worn accelerometers, and height and weight were measured using standardized procedures. Ciclovía participation was self-reported. The analyses included multilevel linear, generalized mixed and generalized additive models.

Results

The mean age of the sample was 10.1±0.7 years, and 49.5% were boys. In the last year, 46% of the children participated in the Ciclovía, and 34% reported participating frequently (at least once per month). No differences were found in the mean minutes of moderate-to-vigorous PA on weekdays between frequent Ciclovía users and sporadic and non-Ciclovía users (72 vs 69; p = 0.09). In contrast, frequent Ciclovía users had higher moderate-to-vigorous PA on Sundays than sporadic and non-Ciclovía users (65.6 vs 59.2; p = 0.01), specifically between the hours of 12:00 and 16:00. In addition, frequent Ciclovía users did not differ from the sporadic and non-Ciclovía users in SED (515.3 vs 521.3; p = 0.19). Frequent Ciclovía users had lower SED on Sundays than the sporadic and non-Ciclovía users (437.7 vs 456.5; p = 0.005). Additionally, frequent Ciclovía users were more likely to be overweight (28.3% vs 20.4% p = 0.01). We did not find differences in participation by sex, and low-to-middle income children were more likely to participate.

Conclusions

The Ciclovías offer an innovative, inclusive recreational space and consequently provide opportunities to increase moderate-to-vigorous PA and reduce SED among children.

Physical activity in adolescents and children and relationship to metabolic health

PURPOSE OF REVIEW

To summarize the recent developments relating to the role of physical activity in improving insulin resistance and metabolic syndrome in children and adolescents.

RECENT FINDINGS

The current literature strengthens previous findings on the relationship between physical activity and metabolic health in children; suggests a protective role for physical activity in the setting of obesity; examines population-specific findings; addresses specific effects of different modalities of physical activity in improving health; reveals potential mediators in the relationship between physical activity and metabolic health; and suggests new markers of metabolic health that could potentially be used as outcomes in future physical activity studies.

SUMMARY

Recent research generally confirms the role of physical activity in decreasing insulin resistance and metabolic syndrome in children and adolescents. However, the current literature is limited by unstandardized research methods and definitions, and also aggregation of different age groups, genders, and weight status. Future research should address these issues to offer targeted physical activity interventions.

Independent and combined associations of physical fitness components with inflammatory biomarkers in children and adolescents

BACKGROUND

We aimed to examine the independent and combined associations of cardiorespiratory fitness, muscular fitness, and motor ability with single and clustered inflammatory biomarkers in children and adolescents.

METHODS

This study included 503 children and adolescents. Cardiorespiratory fitness, upper- and lower-muscular fitness, and motor ability were assessed using field-based tests. Fasting blood samples were obtained to determine the levels of a set of inflammatory biomarkers. Global physical fitness and clustered inflammatory biomarker scores were computed. Associations between physical fitness and inflammatory biomarkers were analyzed through linear regression. Differences in inflammatory biomarker levels between physical fitness tertiles were tested.

RESULTS

Global physical fitness was inversely associated with single and clustered inflammatory biomarkers in children (p < 0.05); and with C-reactive protein, complement factor C4, leptin, and clustered inflammatory biomarkers in adolescents (p < 0.025). Cardiorespiratory fitness and upper-muscular fitness were negatively and independently associated with several single and clustered inflammatory biomarkers in children and adolescents (p < 0.05). Differences were found between the lowest and the highest tertiles of global physical fitness in clustered inflammatory biomarker levels (p < 0.010).

CONCLUSION

Physical fitness was negatively associated with single and clustered inflammatory biomarkers, independently of body mass index. Increasing physical fitness levels in youth might contribute to reduce the cardiovascular risk.

Association between Resting Heart Rate and Health-Related Physical Fitness in Brazilian Adolescents

The aim of this study was to identify the relationship between health-related physical fitness components (aerobic fitness, muscle strength, flexibility, and body fat) and resting heart rate (RHR) in Brazilian adolescents. The study included 695 schoolchildren (14–19 years) from public schools of the city of São José, Brazil. RHR was evaluated using an automated oscillometric sphygmomanometer. Aerobic fitness was assessed by the modified Canadian Aerobic Fitness Test; muscle strength was measured by handgrip dynamometer; flexibility was assessed by the sit-and-reach test; and body fat was assessed indirectly by sum of two skinfold thicknesses (triceps and subscapular). Sociodemographic variables, habitual physical activity, sexual maturation, and body mass index were the covariates. Cardiorespiratory fitness (β = -0.11; 95%CI: -0.14, -0.08) and handgrip strength (β = -0.10; 95%CI: -0.18, -0.01) were inversely associated with RHR in boys. For girls, cardiorespiratory fitness (β = -0.09; 95%CI: -0.12, -0.06) was inversely associated with RHR. In both sexes, body fat (β = 0.50; 95%CI: 0.25, 0.75 for boys; β = 0.17; 95%CI: 0.36, 2.72 for girls) was directly associated with RHR. The RHR is measured more easily than the physical fitness tests, so it is recommended to assess adolescent's heath in large surveillance systems.